Palm-top or hand-held PDA'such as the Palm Pilot® PC or the Casio® E-10 PDA provide a mobile user with “pocket” applications which are controlled using a pen-based input device, buttons and an LCD output. These devices are enjoying increased popularity because of their lightweight construction and compact design (e.g. the devices can fit easily in a jacket pocket or purse and provide useful features such as contact data bases, address books, schedulers, notepads, etc.).
Quite independently of the palm-top PDAs discussed above, CTI systems are known for integrating telephony features with a PC. For example, the Mitel Personal Assistant® integrated telephony system includes a telephone which is connected to a workstation PC via a serial bus or USB, and software for integrating applications running on the desktop PC with telephony features offered by the attached telephone. Thus, for example, the CTI software can be configured so that when an incoming call is received with CLID (Calling Line Identification), a contacts database is accessed and information about the calling party is displayed while the telephone rings. Or, soft keys can be programmed on the telephone, via the computer, to launch an application on the computer, such as a spreadsheet.
An earlier invention, set forth in U.S. Pat. No. 6,647,0103 to Pinard et al. describes the interconnection of a palm-top PDA or computer to a desktop PC which has an attached telephone under its control. In order to control telephony features via the PDA, a communication protocol is used between the PDA and PC for exchanging messages and commands. The PC then processes the call commands received from the PDA and issues further messages and commands to the telephone using a further protocol which is entirely independent of the protocol used to communicate between the PDA and the PC. This introduces complexities and costs in implementing PDA enabled telephony.